1. Technical Field
This invention relates to a plastic double tray system for cultivating plants. The double tray system is configured to be used through an automatic sowing or transporting line. The double tray system comprises a bottom tray and a top tray. In particular, the double tray system is manufactured by thermoforming. In a thermoforming process a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product.
2. Background Art
Such a plastic double tray system is disclosed in EP2.324.696 in the name of the same applicant. This known double tray system is manufactured by thermoforming and has a stiffness and stability comparable to expanded polystyrene trays. The double tray system is configured for seed sowing and seedling transplantation. The double tray system has a top tray and a bottom tray. The top tray includes a plurality of cells and is configured for receiving seeds or seedlings. The bottom tray is configured to support the top tray and to provide rigidity to the double tray system. The bottom tray has a bottom side which has a rectangular outer contour defined by four straight outer edges. In a greenhouse, the double tray system is normally placed on a framework, in which the double tray system is supported by only two horizontally parallel extending support bars of the framework. Two opposite outer edges of the double tray system rests on the two horizontal bars. Hence, the double tray system is only supported at two end regions. A middle region at the bottom side of the double tray system is not supported, such that the double tray system is hanging in between the horizontal bars.
Due to the presence of the bottom tray which supports the top tray, the double tray system has a rigidity which allows such placement on two parallel horizontally extending supports at two opposite outer edges of the double tray system. However, it is still desired to increase the rigidity of the double tray system to prevent the double tray system from hanging down too far in between the two support elements.
The general object of the present invention is to at least partially eliminate the above mentioned drawbacks and/or to provide a useable alternative. More specific, it is an object of the invention to provide a more rigid double tray system.